1. Field of the Invention
This invention relates to perimeter or border lighting for buildings and more particularly to perimeter or border lighting using light emitting diodes as the light source.
2. Description of the Related Art
Perimeter or border lights (xe2x80x9cperimeter lightingxe2x80x9d) are commonly used on buildings to accentuate the structure, to draw customer attention to the building, and to provide safety lighting. Most conventional perimeter lights use neon bulbs for the light source. Some of the disadvantages of neon lighting is that neon bulbs have a relatively short life, are fragile and can consume a relatively large amount of power. Also, neon bulbs can experience difficulty with cold starting, which can lead to the bulb""s failure.
Developments in Light emitting diodes (xe2x80x9cLEDsxe2x80x9d) have resulted in devices that are brighter, more efficient and more reliable. LEDs are now being used in many different applications that were previously the realm of incandescent bulbs; some of these include displays, automobile taillights and traffic signals. As the efficiency of LEDs improve it is expected that they will be used in most lighting applications.
U.S. Pat. No. 4,439,818 to Scheib discloses a lighting strip that utilizes LEDs as the light source. The strip is flexible in three dimensions and is useful in forming characters and is capable of providing uniform illumination regardless of the characters selected for display. The strip comprises a flexible multi-layered pressure sensitive adhesive tape, having a plurality of triangle cutout sections on each side of the tape, with LEDs connected in a series with a resister. One disadvantage of this strip is that it cannot be cut to different lengths for different applications. Instead, different lengths of the strip must be used. Further, the light from the LEDs is not diffused to give the appearance of neon light. This arrangement is not durable enough to withstand the conditions for outdoor use. The flexible tape and its adhesive can easily deteriorate when continually exposed to the elements.
U.S. Pat. No. 5,559,681 to Duarte, discloses a flexible, self adhesive, light emissive material, that can be cut into at least two pieces. The light emissive material includes a plurality of light electrically coupled light emissive devices such as light emitting diodes. The material also includes electric conductors for conducting electric power from the source of electric power to each of the light emissive devices. While this lighting arrangement is cuttable to different lengths, the light it emits is not dispersed so that it resembles neon light. This arrangement is also not durable enough to withstand the conditions for outdoor use.
LEDs have been used in perimeter lighting applications. PCT International Application Number PCT/AU98/00602 discloses perimeter light that uses LEDs as its light source and includes a light tube structure in which multiple LEDs are arranged within an elongated translucent tube that diffuses or disperses the light from the LEDs. The perimeter light is used to highlight or decorate one or more features of a structure, such as a roof edge, window, door or corner between a wall or roof section.
One of the disadvantages of this light is that it cannot be cut to match the length of a building""s structural features. Instead, the perimeter lighting must be custom ordered or it is mounted without fully covering the structural feature. Also, the connectors between adjacent sections of lighting are bulky and result in a visible junction between the sections. In addition, the light""s tube significantly attenuates the light emitted by its LEDs, significantly reducing the light""s brightness. Further, the light does not include a mechanism for compensating for the expansion and contraction between adjacent lights.
The present invention provides an improved elongated perimeter light that uses light emitting diodes (LEDs) as its light source to take advantage of their improved efficiency and longevity. The perimeter light can be connected in series with other perimeter lights, with each of the lights capable of being cut in the field to match the length of the structural feature.
One embodiment of an elongated perimeter light comprises a linear array of light sources (LEDs) that are electrically illuminated. The array of light sources is disposed within an elongated transparent tube, with the tube transmitting and dispersing the light from the array giving the appearance that the array of light sources is a continuous light source. The array of light sources is capable of being cut at intervals down its length to shorten it. The remaining light sources in said array continue to emit light and the tube can be cut to match the length of said array.
The present invention also discloses systems for lighting structural features, with one system according to the present invention comprising a plurality of elongated perimeter lights similar to those described in the previous paragraph. The perimeter lights are electrically coupled in a daisy chain with the electrical power at each of the. perimeter lights being transmitted to the successive light. A mechanism is included for anchoring the plurality of perimeter lights to a structure to illuminate it.
The tube of each perimeter light disperses the light from the light source array without over attenuating it, so that perimeter light provides bright light that simulates the look of straight tube neon. By being cuttable at intervals, custom sized lighting devices do not need to be ordered, reducing the lead-time and expense associated with installing perimeter lighting.
The new perimeter light also provides a new mounting device that includes a mounting button and screw. The buttons are mounted to the structural feature along the line for the new perimeter lighting, preferably using the screws. The back of the new perimeter light is designed to fit over the buttons by either sliding the tube along the button or snapping the tube in place on the button.
The new perimeter light also provides bumpers that fit on the open ends of each tube. The bumpers of adjacent perimeter lights rest adjacent to one another so that they can compensate for the expansion and contraction of the tubes during temperature change. They are also designed to glow and illuminate at the color of the perimeter light. Covers can be used over the junction between adjacent lights, with the covers preferably made of the same material as the tube. The combination of illumining bumpers with the cover section allows the junction to emit light similar to the perimeter light.
The new perimeter light is rugged, energy efficient and easy to install. It is 30 to 70% more efficient than neon lighting and the LEDs can last more than 5 times longer than neon bulbs. It can easily be installed as a replacement to conventional neon lighting.
These and other further features and advantages of the invention will be apparent to those skilled in the art from the following detailed description, taken together with the accompanying drawings, in which: